The purposes of this proposal are (1) to explore the role the nursery school teacher plays in sex role socialization: (2) to trace the development of aggressive, dependent, and cooperative behaviors in preschoolers; (3) to examine these behaviors as they relate to sex, age, intelligence, and socioeconomic status; (4) to see whether nursery school teachers reinforce these behaviors differentially based on the sex of the child; and (4) to see how sex role identification changes during the nursery school years. The above problems will be approached through a cross-sectional and longitudinal study. Three, four and five years olds in nursery school will be followed throughout the nursery school careers. Children will be given pre and posttests each year on various measures of intelligence and sex role identification. Children and teachers will also be observed every two weeks in their classrooms. Concurrent relations between data from these two data sources as well as longitudinal relations will be examined.